12 



BRACHIOPODA. 



2. Ichthyosarcolites has the cavity of the large sph-al or invo- 

 lute fixed valve divided transversely by a number of oblique septa ; 

 the upper valve is probably like an operculum, but this genus is 

 veiy imperfectly known. 



In 1849 Dr. H. G. Bronn {Index Palaontologicus, 8vo,p. 210) 

 divided the Brack iopoda thus : — 



A. genidna. 1. Obolus. 2. Lingula. 3. Siphonotreta. 4. Te- 

 rebratula. 5. Magas. 6. Thecidea. 7- Atrypa. 8. Stringo- 

 cephalus. 9. Uncites. 10. Pentamerus. 11. Camerophoria. 

 12. Enteletes. 13. Spirifer. 14. Trigonotreta. 15. Delthyris. 

 16. Porambonites. 1/. Orthis. 18. Pronites. 19. Hemipro- 

 nites. 20. Orthambonites. 21. Gonambonites. 22, Chonetes. 

 23. Leptaena. 24. Plectambonites. 25. Strophonenia. 26. Pro- 

 ductus 27. Calceola. 



B. Rudistce. 28. Orbicula. 29. Crania. 30. Polyconites. 

 31. Hippurites. 32. Radiolites. 33. Sphaeruhtes. 34. Diceras. 

 35. Ichthyosarcohthus. 36. Caprina. 3/. Requienia. 38. Ca- 

 protina. 39. Plagiopt\'chus. 40. Dipihdia. 41. Monopleura. 



In 1850 Dr. Van der Hoeven {Handbuch der Zoologie, Leipsic, 

 1850, 80. p. 692) divided the Palliobranchiata sew Brachiopoda 

 thus : — 



I. Testa acardis. 1. Lingula. 2. Orbicula. 3. Crania. 



II. Testa cardine instrucia. 4. Calceola. 5. Thecidea. 6. 

 Terebratula. 7- Spirifer. 8. Productus. 



Subclass 1 . ANCYLOPODA. 



The oral arms recurved and aifixed to shelly appendages on the 

 disk of the dorsal valve. Shell minutely and closely punctate. 



Ancvlopoda, Gray, Ann. 4" Mag. N. H. ii. 1848, 436 ; Cat. Brit. 

 Moll. B. M. ; in Wiegm. Arch. 1849, 48. and p. 7- 



Order I. ANCYLOBRACHIA. 



Oral arms affixed to calcareous lamellaj, forming a loop at- 

 tached to the hinge-margin of the dorsal valve, and more or less 

 prominent in its cavity. 



Ancylobrachia, Gray, Ann. N. H. 2nd ser. ii. 435, 436, 1848; 



Cat. Bivalves B. M. ; Wiegm. Arch. 1849, 98 (see p. 8). 

 Brachiopodes brachides (Brachidae) part., D'Orb., Cours Elem. 



Paleont. 80, 1849 (see p. 7). 



